Pendulum mounted heat seal

ABSTRACT

A cap is heat sealed over the mouth of a plastic bottle by a heat sealing mechanism which is mounted on a pendulum whereby the bottle is conveyed past the heat sealing device on a conveyor belt and at the same time heat sealing is accomplished. The pendulum mounting permits the heat seal device to follow the bottle. The cap has a plastic lining within a conventional bottle cap. A typical application is the heat sealing of a bottle containing dairy products, uncarbonated, or carbonated beverages where the bottle is made of polyethylene and the bottle cap is made of aluminum lined on the side adjacent the bottle with polyethylene.

United States Patent [191 Howe [ PENDULUM MOUNTED HEAT SEAL [75]Inventor: George F. Howe, Poplar Grove, Ill.

[73] Assignee: Champion International Corporation, Hamilton, Ohio [22]Filed: Aug. 6, 1971 [21] Appl. No.: 169,754

[52] US. Cl ..53/329 [51] Int. Cl. ..B65b 51/14 [58] Field of Search..53/329 [56] References Cited UNITED STATES PATENTS 3,048,954 8/1962Abel... .....53/329 3,343,336 9/1967 Bradford ..53/329 [451 May 1, 1973Primary Examiner-Travis S. McGehee Attorney-Daniel P. Worth [5 7]ABSTRACT A cap is heat sealed over the mouth ofa plastic bottle by aheat sealing mechanism which is mounted on a pendulum whereby the bottleis conveyed past the heat sealing device on a conveyor belt and at thesame time heat sealing is accomplished. The pendulum mounting permitsthe heat seal device to follow the bottle. The cap has a plastic liningwithin a conventional bottle cap. A typical application is the heatsealing of a bottle containing dairy products, uncarbonated, orcarbonated beverages where the bottle is made of polyethylene and thebottle cap is made of aluminum lined on the side adjacent the bottlewith polyethylene.

10 Claims, 7 Drawing Figures Patented May 1, 1973 s Sheets-Sheet iPatented May 1, 1973' I5 Sheets-Sheet 2 FIG. 5

FIG. 4

Patented May 1, 1973 3,129,897

3 Sheets-Sheet 5 PENDULUM MOUNTED HEAT SEAL SUMMARY OF THE INVENTIONThis invention relates to a pendulum mounted heat seal. One aspect ofthe invention is to provide means for heat sealing a supported film ofplastic to a bottle having a plastic pouring lip, polyethylene being anexample of a useful plastic in each instance. An aspect of the inventionis to provide a pendulum type heat seal whereby the bottle can befollowed by a heat seal means as it moves along a conveyor belt for atime sufficient to achieve the heat seal. One aspect of the invention isto heat seal supported plastic films such as polyethylene lined aluminumfoil bottle caps to the neck or pouring lip of a bottle made ofpolyethylene and containing milk or a carbonated beverage, in connectionwith which the invention will be described.

The advent of the allplastic bottle as a fluid container has broughtwith it service conditions which require an extremely tight seal at thelip or pouring edge. Some of the service and testing procedures are mostrigorous, and even may involve taking an allplastic bottle and squeezingit as hard as possible to see if the cap can be made to leak. In orderto meet the fluid-tight requirements of the trade, it has been suggestedto heat seal the cap to the bottle itself. This means, of course, thatthe heat sealing film and the bottle have to be compatible with eachother so that sealing between them takes place. For example, apolyethylene film inside an aluminum bottle cap will heat sealeffectively to a polyethylene.

Some prior art heat sealing means are incorporated into a device similarto a capping machine whereby the bottles are moved by an indexing devicethrough a se ries of stations. At each station one phase of the heatsealing procedure takes place, and at the end of the heat sealingoperations the bottle is returned to a conveyor means and carried awayto a point where it can be packaged and loaded for transport to theconsumer or ultimate outlet.

The present invention dispenses with the need for a dwell period at eachstation of the indexing device so far as the heat sealing operations areconcerned. The present invention does presuppose that bottles can befurnished with their caps already in place and ready to be heat sealed.

The present invention provides a heat seal means mounted on a pendulum.The ability of the pendulum to swing permits the heat seal means tofollow the bottle for a distance along the conveyor and for a timesufficient to heat seal the film on the bottle pouring lip. Theinvention also involves means to return the mechanism to its startingposition so that a similar set of operations can be repeated on the nextsucceeding bottle.

Other objects, advantages and features will be recognized andappreciated from the following disclosure when read in conjunction withthe FIGS. and claims wherein:

FIGS. 1, 2, and 3 schematically illustrate a front view of the subjectheat seal in a series of positions assumed during a heat sealingoperation, respectively, at the beginning, during and at the end of aheat sealing operation;

FIG. 4 is a schematic side view showing the bottle guides, pedestal, andassociated equipment;

FIG. 5 schematically illustrates a cross-section of the heat head andthe air piping;

FIG. 6 schematically shows the heater and heater control circuit for theheat head;

FIG. 7 schematically shows a :suitable timing adjustment and controlcircuit for use with the apparatus of the other FIGS;

Referring now to FIGS. 1, 2 and 3 there are shown a sequence ofoperations using the present pendulum mounted heat seal assembly to heatseal a cap 2 to the neck or pouring lip of a conventional liquidcontaining bottle 3 while the latter is moved by a conveyor 4 intoengagement with the heat seal assembly 1 and thereby is conductedthrough the heat sealing operation. Preferably as in FIG. I thebeginning heat seal or heat head position is slightly back, i.e.,upstream of the vertical center line of the pendulum: about 2 isdesirable.

The bottle 3 is an all-plastic bottle suitable for containing anuncarbonated beverage. Typical is a A: pint bottle made of polyethylene,containing an aqueous artificially flavored beverage (grape, raspberry,orange, etc.) and capped in a conventional manner by a conventionalplastic lined aluminum foil cap 2. The polyethylene cap lining is on theinside of the cap and physically contacts the lip of the bottle. In thisinstance, the cap has a layer of polyethylene coated on a layer ofaluminum foil. The bottle may also be polystyrene in which case thepolyethylene lined foil cap will also heat seal to it. On some occasionsthe cap is made of an aluminum foil-wax paper combination that isovercoated with a polyethylene type plastic. The former cap is preferredbecause of the simplicity of its construction and lower cost.

In any event, as seen in FIGS. 1., 2 and 3 the conventional conveyorbelt 4 moves the bottle 3 past the heat sealing assembly 1. As thebottle approaches (FIG. 1) the assembly, and electric eye or somesimilar sensing mechanism (such as a limit switch or microswitch) 5senses the presence of the bottle and actuates a control system totrigger a series of events, one of which is to lower the heat head 7down on to the bottle (FIG. 2). The heat head 7 contains the heatsealing means per se. The heat head is attached to the end of a pistonrod 8 of a pneumatic cylinder 9. The piston rod may have cooling fins 6thereon for heat dissipation. The heat head while engaged with the cap(FIG. .2) applies heat to the cap for a time sufficient to achieve thedesired amount of heat sealing. As illustrated in FIG. 3, at the end ofsuch time the heat head is withdrawn by actuating the cylinder in thereverse direction (up) and the system is reset, i.e., returned to thestarting position of FIG. 1.

The heat seal assembly 1 is mounted one standard pedestal 10 (FIG. 4)which provides a manual vertical height adjustment means 12 and can bereadily moved. This particular type of pedestal is. commonly found indairies and similar bottling operations. Its use here minimizes theamount of additional equipment to be acquired when the present inventionis placed in operation. In addition, it emphasizes the ease with whichthe present invention can be installed on an existing bottling linemerely by positioning it at an operating position on the line andwithout requiring a lot of intricate mechanical connections and timingbetween the existing line and the heat sealing device.

The pedestal illustrated in FIG. 4 comprises a base 14 under which areleveling screws 15. A column 17 means extends upwardly from the base.The height adjustment means 12 may comprise a gear and ratchet assemblyof conventional sort which drives a movable portion of the column upwardout of the base or lower portion of the pedestal or it may be ascrew-type clamp that keeps column 17 in place. The heat seal pendulumassembly 1, control box, and other mechanisms are attached to the upperend of the column 17.

The pendulum assembly 1 includes the heat head 7 and air cylinder (i.e.,neat head moving means) 9, sup ported on a pivot plate 20 supported by abolt 21, acting as an axle or pivot shaft, from a pendulum supportmember 22 which is in turn secured by bolts 23 27, brackets and the liketo the upper end of the column. In this way the entire assembly 1 can bemade up at a factory, shipped to a dairy, and attached to the pedestal10 which, as already noted, is a piece of standard equip ment arounddairies. Of course, other types of support means than the pedestalillustrated can be used.

The pivot plate 20 may have a number of pivot holes 29 whereby differentamounts of balance, back and forth swing, etc., can be achieved. Boltedto the support plate is a set of springs 30, illustrated as leafsprings, which biases the pendulum or pivot plate back toward the pivotadjustment 33 which acts as a stop. The pivot adjustment advantageouslymay comprise a bolt 34 secured in a threaded opening on a bracket or car35 which extends from the support plate. The bolt may, if desired, haveone or more lock nuts attached thereto. The purpose of the pivotadjustment 33 is to regulate the amount of back swing and to positionthe pendulum and therefore the heat seal for the initial portion of thestroke.

Also supported on the pendulum assembly on top of cylinder 9 solenoidoperated valve 39 for controlling air going into and out of the aircylinder and the heat head 7 on the end of the air cylinder plunger. Theheat head 7 (FIG. 5) comprises an insulated upper body 40 surrounding aplurality of heaters 41 arranged within the head, a heat conductive bodywith a flat cap contacting surface 42 engaging the top of the bottle cap2 and the electrical leads 44 connecting the heaters to the controlcircuit of FIG. 6. The entire heat head 7 is attached to the lower endof the air cylinder plunger. The air cylinder may be either singleacting (as in FIG. 5) or double acting. As shown in FIG. 5 the aircircuit includes the solenoid operated valve 39 with the necessary airpiping 53 to control the flow and release of air under pressure to oneor both ends of the air cylinder depending on whether it is Single ordouble.

The presence of the bottle 3 between cell 5A and lamp 58 (mounted onbracket 56) triggers the electric circuit shown in FIG. 7, therebyactivating the solenoid 39 which opens the valve to admit air into theair cylinder 9 to drive the heat head 7 down on the bottle. The bottlethen is moved by the conveyor belt until it reaches the position of FIG.3 where disengagement of the cap and heat head take place in response tothe first to occur of one of two events either the appearance of anotherbottle at the electric eye which causes an electrical and mechanicalreset of the system or the expiration of the dwell time to which theelectrical control circuit of FIG. 7 has been adjusted. The dwell timeis the time interval that the heat head is in heat sealing contact withthe bottle cap.

The air circuit shown in FIG. 5 for bringing compressed air to the heathead 7 may be connected to any suitable source of compressed air. On thepivot plate are supported a filter 50, pressure regulator 51, an oiler52 for the air supply whereby dirt and oil can be removed, the pressureregulated to the pressure required by the air cylinder, and a sufficientamount of oil added to the air stream to keep the cylinder in properoperation. Flexible conduits, e.g., rubber or plastic hose 53 connectsthe filter 50 to an air supply and the oiler 52 to the cylinder. Thepneumatic control circuit includes the three-way valve 39 which isoperated by the electrical solenoid 39A (FIG. 7) to either admit air toone end of the single acting cylinder, or to release pressure thereonwhereupon the return spring of the single acting cylinder will returnthe piston to its initial position. The three-way valve 39 is providedto regulate the flow of compressed air to the upper end of the cylinderor to exhaust it to the atmosphere thereby releasing pressure on theupper end of the cylinder, in a manner which is well known in the art.

In FIG. 6 is shown the electrical control circuit for selecting andcontrolling the amount of electricity supplied to the plurality ofparallel-connected electric heaters 41 which are part of the heat head7. The leads 44 supply electricity, preferably V. A.C., to this circuit.The remainder of the circuit is in series with the heaters and includesa control potentiometer 45 for regulating and adjusting the amount ofpower supplied to the heaters 41 and means for controlling the voltagesupplied to the heaters 41 in accordance with the setting of the controlpotentiometer.

The voltage control means and the control potentiometer comprise anumber of series parallel circuits having semi-conductor control meanstherein. The voltage control means has a R-C timing network to assist incontrolling the voltage applied to the heaters. Connected in series withthe control potentiometer is a first capacitor 45B. In addition,connected in parallel with the potentiometer and capacitor are secondand third resistors 46A, 46B and second and third capacitors 47A, 47B,respectively in series with each other. A fourth adjustablepotentiometer 48 is connected between the control potentiometer and thesecond resistor. A bi-directional triggered diode semiconductor 49A(such as the Diac sold by General Electric) is connected from a commonjunction between the first and fourth potentiometers and the gate oftransistor 498 which serves as an AC. semiconductor switch. Thecollector and emitter of the transistor 49B are connected in series withresistance load 41 to leads 44. A control system of the sort justdescribed may be obtained commercially from General Electric Company astheir standard Triac unit, but without the heaters and the controlpotentiometer which must be added.

In FIG. 7 is shown a timer control circuit for regulating the dwelltime, i.e., the time that the heat head 7 is held in engagement with thebottle cap 2 to achieve the requisite heat sealing. This is the timeinterval between the first instance of heat sealing engagement (at aboutor shortly after the FIG. 1 position) and the disengagement of the heathead (at about or shortly before the FIG. 3 position). This in effect isa timing circuit which is triggered into operation by receipt of asignal from the lamp SE at the cadmium cell 5A portion of the electriceye assembly 5 responsive to (FIG. 1) the bottle 3 interrupting thelight beam normally transmitted between the lamp 5B and the cell 5A.Upon this occurring, the system functions to complete an electricalcircuit through leads 60 to energize solenoid 39A of the control valve39 and cause air to be admitted to the upper end of the air cylinder ofFIG. 5, the piston to move downward, and the heat head 7 to engage thebottle cap 2. This engagement remains until the timing circuit of FIG.'7 breaks the circuit to the solenoid 39A and causes disengagement byexhausting air from the upper end ofthe air cylinder of FIG. 5.

The electric circuit of FIG. 7 provides a timing circuit which can beset for varying amounts of time depending on the speed that the bottleis moved by the conveyor, the difficulty of heat sealing caused by suchfactors as the thickness and materials of the bottle cap and the bottle,the amount of materials spilled on the bottle neck during filling whichmight interfere with heat sealing (this, however, has not been a seriousproblem), and other factors.

The FIG. 7 timing circuit includes a dwell control potentiometer 61which is adjusted to provide the desired amount of dwell time. A timedelay relay 62 is provided in conjunction with this, including relaycoil 62A which operates the contacts 62B to close same during the dwelltime, i.e., while the heat head is engaged with the bottle cap. Therelay contacts 628 are normally open,are closed responsive to the coilbeing energized when the bottle appears at the electric eye, and remainclosed until the dwell time is exhausted or until the electric eye 5(which includes the lamp 5B and cell SA) detects another bottle andprovides a signal to reset.

In operation power is supplied from the leads 44 through a power supplytransformer. Cadmium cell 5A detects when a bottle breaks the light beamfrom lamp 5B and thereby completes a circuit through air cylindercontrol relay 64 by causing the transistor 65 to act like a closedswitch, completing the circuit through the coil 64A of the air cylindercontrol relay. When the last stated even occurs, the relay completes thecircuit across normally open contacts 64B and temporarily breaks thecircuit through normally closed contacts 64C.

When the relay 64 is actuated, normally closed contacts 64C are openedwhich prevents the air cylinder solenoid 39A from being immediatelyactuated because of the break in the circuit at this point. Thiscondition exists until the electric eye light beam is broken by reasonof the bottle being moved by the conveyor into the path of the electriceye light beam which de-energizes relay 64, closes contacts 64C to theirclosed condition whereupon solenoid 39A is energized and theair cylinder9 operates. The timing circuit for relay 62 includes the potentiometer61 and the capacitor 65 and prevents relay 62 from changing its positionfor the dwell time. At the end of the dwell time the timing circuitcauses the coil 62A to de-energize whereupon the air cylinder is causedto exhaust.

Should a bottle appear at the electric eye during the dwell timeselected by adjustment of potentiometer 61,

energizing of relay 64 breaks the circuit through contact 64C therebycausing disengagement of the heat head per FIG. 3 (because air solenoid39 is thereby deenergized) and mechanical reset of the system under thebias of springs 30, and then a repeat of the aforesaid operations whenthe second bottle breaks the light beam.

The invention claimed is:

I. A heat sealer for heat sealing a heat sealable closure to a containerhaving an opening surrounded by heat sealable material, the closurebeing positioned over the container opening before movement by conveyingmeans into engagement with the heat sealer, which heat sealer comprisesa heat head,

a support,

a pivot plate revolvably mounted on said support for arcuate movement toand fro in a manner substantially like that of a pendulum, and meansmounted on said pivot plate on which said heat head is mounted formoving said heat head into and out of contact with such closure.

2. A heat sealer according to claim 1 wherein said pivot plate ismounted on said support to swing in a plane substantially parallel tothe plane the closure in place on the container is moved through.

3. A heat sealer according to claim 1 further compring biasing means forresetting said pivot plate by moving said pivot plate when said heathead is out of contact with an object to be sealed to an initialposition.

4. A heat sealer according to claim 1 further comprising an adjustablestop member to limitthe arcuate movement of said pivot plate.

5. A heat sealer according to claim 1 wherein said means for moving hasa reciprocal motion relative to said pivot plate for moving into,maintaining, and moving out of engagement with said closure on saidcontainer.

6. A heat sealer according to claim 1 further comprising a conveyor formoving a series of such objects linearly seriatim to a position whereeach object is initially engaged by said heat head and continued to beso moved by said conveyor with said heat head in contact for a time atleast sufficient for heat sealing to occur.

7. A heat sealer that swings pendulum-like through an arc and heat sealsan object moved in substantially a line into heating engagementtherewith and which for heat sealing objects comprises a heat head,

a support member,

a support plate revolvably mounted on said support member, and meansmounted on said support plate on which said heat head is mounted formoving said heat head into and out of contact with object to be heatsealed,

wherein said support plate is mounted to swing in a plane substantiallyparallel to the plane the object to be sealed is moved through,

further comprising biasing means for a reset action conducted by movingsaid heat head when out of contact with an object to an initialposition.

8. A heat sealer according to claim 7 further com- 5 prising anadjustable stop member to limit the revolvable movement of said supportplate.

9. A heat sealer for heat sealing objects comprising a heat head,

a support plate revolvably mounted on a support,

and

means mounted on said support plate on which said heat head is mountedfor moving said heat head into and out of contact with object to be heatsealed,

wherein said support plate is mounted to swing in a plane substantiallyparallel to the plane the object to be sealed is moving through,

biasing means for a reset action conducted by mov- 10 ing said heat headwhen out of contact with an ob-

1. A heat sealer for heat sealing a heat sealable closure to a containerhaving an opening surrounded by heat sealable material, the closurebeing positioned over the container opening before movement by conveyingmeans into engagement with the heat sealer, which heat sealer comprisesa heat head, a support, a pivot plate revolvably mounted on said supportfor arcuate movement to and fro in a manner substantially like that of apendulum, and means mounted on said pivot plate on which said heat headis mounted for moving said heat head into and out of contact with suchclosure.
 2. A heat sealer according to claim 1 wherein said pivot plateis mounted on said support to swing in a plane substantially parallel tothe plane the closure in place on the container is moved through.
 3. Aheat sealer according to claim 1 further compring biasing means forresetting said pivot plate by moving said pivot plate when said heathead is out of contact with an object to be sealed to an initialposition.
 4. A heat sealer according to claim 1 further comprising anadjustable stop member to limit the arcuate movement of said pivotplate.
 5. A heat sealer according to claim 1 wherein said means formoving has a reciprocal motion relative to said pivot plate for movinginto, maintaining, and moving out of engagement with said closure onsaid container.
 6. A heat sealer according to claim 1 further comprisinga conveyor for moving a series of such objects linearly seriatim to aposition where each object is initially engaged by said heat head andcontinued to be so moved by said conveyor with said heat head in contactfor a time at least sufficient for heat sealing to occur.
 7. A heatsealer that swings pendulum-like through an arc and heat seals an objectmoved in substantially a line into heating engagement therewith andwhich for heat sealing objects comprises a heat head, a support member,a support plate revolvably mounted on said support member, and meansmounted on said support plate on which said heat head is mounted formoving said heat head into and out of contact with object to be heatsealed, wherein said support plate is mounted to swing in a planesubstantially parallel to the plane the object to be sealed is movedthrough, further comprising biasing means for a reset action conductedby moving said heat head when out of contact with an object to aninitial position.
 8. A heat sealer according to claim 7 furthercomprising an adjustable stop member to limit the revolvable movement ofsaid support plate.
 9. A heat sealer for heat sealing objects comprisinga heat head, a support plate revolvably mounted on a support, and meansmounted on said support plate on which said heat head is mounted formoving said heat head into and out of contact with object to be heatsealed, wherein said support plate is mounted to swing in a planesubstantially parallel to the plane the object to be sealed is movingthrough, biasing means for a reset action conducted by moving said heathead when out of contact with an object to an initial position, and aconveyor for moving a series of such objects linearly seriatim to aposition where each object is initially engaged by said heat head andcontinued to be so moved by said conveyor with said heat head in contactfor a time at least sufficient for heat sealing to occur.
 10. A heatsealer according to claim 9 wherein said means for moving is areciprocable fluid operated motor.